The guru of modern thinking about the significance of materials is Professor Vaclav Smil of the University of Manitoba, described by Bill Gates as “my favourite author”. In his view, physical substances remain central to modern economies in spite of all the advances in information technology, and the apparent evidence of dematerialisation is often misleading.

In his latest book, Making The Modern World, he cites computer-aided design. The Boeing 747, designed in the 1960s, required 75,000 drawings with a total weight of 8 tonnes. Using computer-aided design (CAD) for the 767 in the 1990s did away with all that paper, and cut costs and design time.

However, as Prof Smil points out, the CAD system required computers, data storage, communications, screens and electricity to run. Given the complexity of the systems involved, it is far from obvious that the switch to CAD cut United States use of materials overall.

It is true that in computing power there has been spectacular dematerialisation. All the computers sold in the world in 2011 weighed 60 times as much as the total sold in 1981, but had 40 million times the memory.

But where microchips are not the dominant component of the total design, Prof Smil wrote, there has been no even remotely similar mass decline. In some sectors, technological progress has actually made products more “material”. The Ford Model T, one of the first automobiles, weighed 540kg; the F-150 pick-up, which is its most popular model today, weighs more than 2 tonnes.

Prof Smil’s conclusion is that while dematerialisation, in the sense of reduced material use for every dollar of gross domestic product, has been a trend for decades and can continue into the future, an absolute reduction in the world’s use of natural resources is highly unlikely. If growth continues, at some point those resources will run low.

While we do not know when we will hit the limits of materials usage, we know they are out there somewhere. Tensions such as the dispute over rare earths or rising commodity costs could have serious consequences for growth.

Prof Smil’s answer is that we need to think about rational futures of moderated energy and material use. As he admits, though, it is hard to see any political leaders being prepared to offer their citizens less and less in the future; particularly not in emerging economies where billions are hoping to come closer to developed world lifestyles.

This latest argument is pretty content-free. We continue to use minerals freely because they're pretty abundant. Where there are limits, like copper or a few "rare" earths, there are good substitutes. There's no sign of resource-based limits to growth.

@Nick - Smil is one of those seemingly smart people who does have a lot of issues. You're right that his car example (and others) isn't particularly relevant as there is no meaningful limit on the resource supply (you could make the same argument about house sizes too I suspect).